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The Role of Statistics Post-Market
Jay Herson, Ph.D.Johns Hopkins University
Sept 29, 2006
Post-Market Trials
• Phase IV• Label extension or modification• Surveillance• Investigator INDs• Seeding Studies• Biostatistician input much needed
Roles
• Role should not be described as a list of tasks
• Role of the biostatistician in post-market industry trials is to be an advocate for GOOD SCIENCE.
Wisdom
• Good Science is Good Business but• Good Business is not necessarily
good science• Credible and timely results is good
business in the long run
Good Science—Design Stage
• Objectives• Primary and secondary endpoints• Eligibility• Power and precision• Doses, regimens• Control Group• Non-inferiority trials
Good Science--Results
• Results available to patients and physicians
• Publication regardless of results• Clear definition of original objectives
of the trial• Appropriate measures of precision,
exposure• Post-hoc power
Advocate
• Independent Review throughout the trial
Post Market Trials
Then and Now
Large Trials
• GUSTO—t-PA vs streptokinase• ATLAS—adjuvant tamoxifen• COMMIT—acute MI asparin vs
clopidogrel• CPPT—lipids, cholestiramine• CONCORDE—HIV, AZT• WHI
Surprising Results
• BHAT—propranalol• CAST—encainide, flecainide
Cooperative Meta Analyses
• ATT—antithrombolytics• EBCTCG—early breast cancer
Oncology—Practice Changing Trials
• Aromatase inhibators—breast cancer• bevacizumab-VEGF, colorectal• trastuzimab—breast cancer• taxanes—lung, ovarian• platinum—lung ovarian
However….• Most of the trials just referenced
were not conducted by industry
Industry Sponsorship
• Pre-Market---Science / Regulatory driven
• Post-Market—Marketing driven
Marketing Influence
• No trials undertaken whose results could threaten market share
• Results suppressed if they threaten market share
Industry Sponsorship• Phase IV—Under control of marketing• Anti-depressants—19/21 trials head-
to-head sponsors product superior.– Low dose for competitor– Different schedules– Simple conditions– Not double blind
The Non-Inferiority Complex
• Sloppy trials• Result is under control of sponsor• Delta• Active control• Sub-potent dose• Terminate before effects• Imprecise measurement
Industry Sponsorship
• Publication bias• Results not matched with original
objectives• Cox-2 inhibitor trials / bureaucracy
Industry Sponsorship
• Advertising agency purchased CRO• Seeding studies• Design problems• Organizational problems
Good News
• William Olson, Ortho-McNeil• Patent 6,339,105• A regimen for the administration of
tramadol for the treatment of analgesia
• Slower titration rate• Reduction in side effects
Opportunities
• Bayesian design and analysis• Testing grounds—adaptive designs• Meta analysis
– Methodology– Fixed vs Random Effects– Mixed models
A. Mugglin—Medical Devices
• Fine illustration of the role of statisticians
• Interesting SCD-HeFT cost-effectiveness study
• How do results of this information get disseminated to stakeholders—patients and their caregivers?
• Should not be used as sole justification for higher prices for the product.
Mugglin--Future
• Globalization• Aging of populations• Cost-effectiveness• IOM recommendation• Genetics
Genetics• Revisit approved but unpopular
drugs due to knowledge of what DNA is associated with response, low toxicity.
• bucindolol vs other beta blockers for heart failure
• tamoxifen vs aromatase inhibitors in breast cancer
Gould--Surveillance
• fialuridine (FIAU), 1993• Good list of limitations
(Considerations and Issues)• Accumulating information of RR and
the lower 5% point---how long to watch a signal?
• Retrospective pharmacovigilence
Gould--Bayes
• Definitely a role for Bayesian methods here. The sooner the better.
• Empirical Bayes a good start• Sponsor safety database• Oncology—MedDRA vs CTC 3.0
Gould--Contribution
• Shows the contribution a statistician can make to a difficult problem by thinking through the problem
• Hope for a common ground between plaintiffs and industry
• To deny the implications of this type of analysis is to deny our ability to reason
Marinac-Dabic FDA/CDRH
• Sources of data• Areas requiring attention• Motivate good science• Post-market surveillance for the
elderly• Passive reporting system for high
quality post-market surveillance data
• Thank You